Maidstone Museum and Bentlif Art Gallery's new extension is a modern classic

Maidstone Museum and Bentlif Art Gallery's new extension designed by Hugh Broughton

What on earth is that goldy-looking thing in the middle of Maidstone, that supersized Benson & Hedges fag packet pretending to be a building? Ah, it must be one of those World-Class Places that the government is promoting – as in "iconic" architecture. Not so. The new extension of Maidstone Museum and Bentlif Art Gallery, designed by Hugh Broughton, is a counter-blow to the government's witless, developer-friendly assumption that places, and lives, can be transformed by blinged-up buildings marketed as world class.

Broughton's new architecture may look glitzy, but it's actually simple, effective, and absolutely local in the way it has made the museum a much more effective cultural, and urban, focal point. And it's gained 30 per cent more exhibition space, with a doubling of storage capacity.

The museum's mélange of 16th, 19th-and 20th-century buildings, containing wide-ranging collections, has been recast along two of its edges, and the copper-skinned extension holds aloft a delightful glass room.

Broughton has remodelled the museum's original southeast corner, built in 1878, smartened up two original galleries, turned a skinny goods delivery space into an exhibition area, and created a fine new space for the museum's internationally important Japanese collection.

www.museum.maidstone.gov.uk